Town of Lexington, MA GIS Viewer

Flood hazards include:FEMA 100 and 500-year floodplainsStorm surge- high frequency (Category 1-3) and low frequency (Category 4 & 5)Sea level projections*King tide + sea level projections*10-year storm surge + sea level projections **NOAA Intermediate Low and Intermediate High for 2020, 2040, and 2070 Each AHI point (development from the Assisted Housing Inventory) for the Tampa Bay area is assigned a composite exposure value calculated by summing the presence of potential flood hazards over the time period 2020 - 2070, with a maximum score of 23. Parcel exposure, rounded to the nearest whole number, is as follows:<!- "None" = 0 composite exposure<!--"Low" = 1 - 7 composite exposure<!--"Medium" = 8 - 15 composite exposure<!--"High" = 16 - 23 composite exposureData sources include:The residential parcel data layer is “FLORIDA PARCEL DATA STATEWIDE – 2020,” which is obtained from Florida Geographic Data Library (FGDL) (https://fgdl.org/metadataexplorer/explorer.jsp). Metadata for this layer can be found here: https://www.arcgis.com/home/item.html?id=768fcd89d9c94d7db994178db11bcf78Affordable market-rate housing (or “Naturally Occurring Affordable Housing” (NOAH)) is determined for single-family (SF), multifamily (MF), and condominium properties in the Tampa Bay region. Details on the methodology are available from the UF Shimberg Center.<!--The Assisted Housing Inventory (AHI) data was sourced from the Florida Housing Data Clearinghouse on April 25, 2019. (See https://flhousingdata.shimberg.ufl.edu/assisted-housing-inventory and the associated “AHI User Guide” https://flhousingdata.shimberg.ufl.edu/AHI-user-guide.)<!--FEMA floodplain data are “FLOOD HAZARD ZONES OF THE DIGITAL FLOOD INSURANCE RATE MAP (DFIRM) IN THE STATE OF FLORIDA - OCTOBER 2020,” and obtained from Florida Geographic Data Library (FGDL) (https://fgdl.org/metadataexplorer/explorer.jsp). Metadata for this layer can be found here https://www.fla-etat.org/meta/dfirm_100_floodzones.xml. Storm surge data were obtained from the NOAA National Hurricane Center’s National Storm Surge Hazard Maps, and depict projected surge inundation based on SLOSH modeling and coastal Digital Elevation Models (DEMs). The data and metadata can be found here: https://www.nhc.noaa.gov/nationalsurge/.o Storm surge exposure is divided into low frequency (categories 4 & 5) and high frequency (categories 1-3) groups. This grouping was determined based on the frequency of occurrence of direct hurricane impacts to Florida over the period of 1851 to 2018 (https://www.aoml.noaa.gov/hrd-faq/#1569507388495-a5aa91bb-254c). <!--Sea level rise (SLR) projections were developed by the Tampa Bay Regional Planning Council (TBRPC) based on the 2017 NOAA sea level rise curves (“Intermediate High” and “Intermediate Low”), local tidal data, and Digital Elevation Model (DEM) data using the TBRPC’s Flood Master tool. It should be noted that the Intermediate High projections are consistent with the Florida’s 2021 "Statewide Flooding and Sea Level Rise Resilience" bill and the FEMA National Flood Insurance Program.o Sea level rise projections were calculated for each of the SLR scenarios for the years 2020, 2040 and 2070, and then adjusted using the St. Petersburg tide gauge (for Pinellas, Manatee, Sarasota, Hillsborough and Pasco counties) and the Cedar Key gauge (for Citrus and Hernando counties). Reference tide gauges were based on recommendations from the Climate Science Advisory Panel of Tampa Bay, and tidal data was obtained from the US Army Corps of Engineers SLR calculator: https://cwbi-app.sec.usace.army.mil/rccslc/slcc_calc.html. Mean tide was selected for all runs performed for this project. o TBRPC’s Flood Master tool uses Digital Elevation Models (DEMs) to then determine the areas of inundation associated with the projected sea level rise, as well as the high tide and 10-year event storm surge scenarios. Additional tide gauges and drainage basin boundaries within the TBRPC region were used to refine the inundation estimations. Additional information and the data can be found here: https://opendata-tbrpc.hub.arcgis.com/.<!--King tide + SLR / 10-year storm surge + SLR projections. High tide flooding is derived from “coastal flood frequency” data layers obtained from NOAA Digital Coast (https://coast.noaa.gov/slrdata/), and the 10-year storm surge is derived from a SLOSH study conducted by AECOM. TBRPC combined these two layers with SLR scenarios to provide further inundation analysis. <!--Satellite imagery of flooded land area post-Hurricane Irma (September, 2017) was sourced from Atmospheric and Environmental Research (AER; https://www.aer.com/). This is an experimental flooded land composite satellite data product derived from the NASA Advanced Microwave Scanning Radiometer group of sensors (AMSR-E, AMSR2: https://earthdata.nasa.gov/about/sips/sips-amsr-e-2), the Global Precipitation Measurement Microwave Imager (GMI: https://pmm.nasa.gov/gpm/flight-project/gmi), and the Special Sensor Microwave Imager (SSM/I: https://podaac.jpl.nasa.gov/SSMI). It should be noted that this product was used to provide an interim indication of interior land areas prone to flooding. (Atmospheric and Environmental Research, 2017, ARC Flood Extent Depiction Algorithm Description Document, AFED Version V03R01, Document Revision R03, Lexington, MA. 56pp.) <!--CDC Social Vulnerability Index (SVI) indicates the relative vulnerability of every U.S. Census tract. Overall vulnerability combines four themes including 1) Socioeconomic Status, 2) Household Composition and Disability, 3) Minority Status and Language, and 4) Housing Type and Transportation. These four themes are in turn based on groupings from 15 factors such as unemployment, minority status, disability, etc. Thus, each tract receives an overall ranking as well as a ranking for each of the four themes. In addition, a relative Measure is included (expressed as a percentile), which indicates the vulnerability ranking by tract and parcel. Values range from 0 to 1, with 1 being the most vulnerable. Additional information on the SVI layer can be found here: https://www.atsdr.cdc.gov/placeandhealth/svi/documentation/SVI_documentation_2018.html